This patch fixes

drivers/mtd/nand/atmel_nand.c:372: warning: 'part_probes' defined but not used

which is issued when CONFIG_MTD_PARTITIONS is defined but
CONFIG_MTD_CMDLINE_PARTS not.
Signed-off-by: NAndreas Bießmann <biessmann@corscience.de>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>